Age-related changes in bone mass have been demonstrated in both men and women. Age and sex related differences hormones, nutritional and physiological variables involved in bone turnover are important in elucidating changes in bone physiology in normal aging and disease. The relationship of muscle strength, as estimated by concentric torque in the lower extremity, to bone mineral density, was evaluated in 80 men and 73 women ranging from 23 to 88 years of age. These normal volunteers from the Baltimore Longitudinal Study of Ageing had highly significant negative correlations of age with muscle strength and bone mineral density. At the same time muscle strength was positively correlated with estimates of bone mineral density. When the effect of age was analyzed by multiple regression techniques there was no age-independent contribution of muscle strength to bone mineral density in women, but there remained a significant relationship of muscle strength to bone mass in men with stronger men having greater bone mass at any age. This different strength-bone relationship in men and women may indicate a role for anabolic sex hormones in the maintenance of bone mass during aging.